Ambiguous Artifact ID

The artifact hash prefix 4971 is ambiguous and might mean any of the following:

1. 497166ca32f04bf23e8d0c3972e612c394c0f8804133933dbef5a21479221f4c -

   • File internal/manifest/dephantomize.go — part of check-in [0fd2a507b8] at 2026-07-24 15:27:03 on branch trunk — perf: route history-walking expansions through content.Cache (#151) (#153)

     The buffer-reuse fix in #145/#150 cut the cost of expanding one delta chain once. It did nothing for callers that expand many versions of the same artifact in a single operation: each bare content.Expand still replayed the whole O(depth) chain, so a walk over N overlapping revisions cost O(N^2) blob reads even though content.Cache already existed for exactly this pattern.

     Audited every non-test content.Expand caller. Two access patterns genuinely repeat over overlapping delta chains and are now routed through a per-operation content.Cache:

     - annotate walks every revision of one file along the parent chain. content_deltify stores each older file blob as a delta against its successor, so the per-revision expansions are all walks of the same few chains. One cache threaded through the walk (file blob + manifest listing via new manifest.ListFilesCached/GetManifestCached, both nil-passthrough so existing callers are unchanged) turns it linear. Measured on a deltified 150-revision file: 1.60s -> 0.65s (2.5x), 764k -> 308k allocs; the win grows with history depth.

     - verify.Verify and verify.Rebuild sweep every blob more than once (Rebuild: checkBlobs + rebuildManifests + rebuildTags x2). A single cache shared across the pass walks each chain once instead of once per sweep and amortizes overlap within each sweep. Measured on a 150-revision two-file repo: Rebuild 3.34s -> 0.068s (48x), 4.59M -> 98k allocs.

     Callers that only ever touch the tip or make a single pass over distinct blobs (branch create, merge-config load, R-card / delta manifest build, MergeParentFiles, crosslinkSingle, shun undelta, pairwise Diff) are left on bare Expand, each with a comment stating why a cache cannot amortize their access.

     No behavior change: expansion output is byte-identical, verified across the modernc and ncruces drivers with REQUIRE_FOSSIL_BIN=1 cross-checks and the DST suite. (user: [email protected], size: 4074) [annotate] [blame] [check-ins using]

2. 4971ca697b8b0705153a4952987bd47fa1ee118ad5aa30ae8bff9be88debf90b -

   • File db/driver/ncruces/go.sum — part of check-in [c5e189600f] at 2026-07-19 11:08:51 on branch trunk — chore(deps): bump the go_modules group across 2 directories with 1 update (#42)

     Bumps the go_modules group with 1 update in the / directory: [golang.org/x/crypto](https://github.com/golang/crypto). Bumps the go_modules group with 1 update in the /observer/otel directory: [golang.org/x/crypto](https://github.com/golang/crypto).

     Updates `golang.org/x/crypto` from 0.49.0 to 0.52.0 - [Commits](https://github.com/golang/crypto/compare/v0.49.0...v0.52.0)

     Updates `golang.org/x/crypto` from 0.49.0 to 0.52.0 - [Commits](https://github.com/golang/crypto/compare/v0.49.0...v0.52.0)

     --- updated-dependencies: - dependency-name: golang.org/x/crypto dependency-version: 0.52.0 dependency-type: direct:production dependency-group: go_modules - dependency-name: golang.org/x/crypto dependency-version: 0.52.0 dependency-type: indirect dependency-group: go_modules ...

     Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> (user: [email protected], size: 4573) [annotate] [blame] [check-ins using]